It is desired in terms of preventing a leakage of information etc to check whether or not a content (moving picture) of moving picture data etc streaming on a network is similar to a content of predetermined moving picture data. A terminology of “similar or similarity” embraces “coincident or coincidence”.
A majority of moving picture data (moving picture files) streaming on the network undergo an encoding process in order to compress data sizes. Further, the moving picture data provided through a majority of recording mediums are also encode-processed.
Even in the case of the same moving pictures, if encoding methods, compression rates, etc thereof are different, the encode-processed moving picture data are different from each other. It is therefore difficult to determine whether or not the content (moving picture) of one set of moving picture data is similar to the content (moving picture) of another set of moving picture data by comparing the encode-processed moving picture data with each other.